1. Field of the Invention
This invention relates to protecting data and more particularly relates to continuously protecting digital data.
2. Description of the Related Art
A data processing system stores and processes large amounts of valuable data such as financial transaction records, shipping and inventory records, and service transaction records on data storage devices. The data may be lost if a data storage device fails, the data becomes corrupted, or if data is erroneously entered. Because the cost of losing data is high, the data processing system may employ redundant data storage devices to increase data availability and protect against loss. For example, the data processing system may include a redundant array of independent disk (“RAID”) storage system that redundantly stores data on multiple disks. The data processing system may continue to store and retrieve data even if a disk data storage device in the RAID system fails.
The data processing system may also backup data to protect against data loss. For example, the data processing system may save the contents of one or more data storage devices to magnetic tape or the like on a regular basis such as nightly. If data is subsequently lost from a data storage device, an instance of the data from the time of the backup may be recovered. Unfortunately, there is typically a significant difference between the data processing system data at the time of the data loss and the backup data. Therefore data backups do not completely protect against data loss.
As a result, the data processing system may make frequent flash backups of data by copying the data to backup data storage devices. Flash backups further reduce the amount of data that is irretrievably lost as the time interval between flash backups is often small.
Unfortunately, frequent flash backups offer less protection against data loss due to data that is corrupted or erroneously entered, data that is referred to herein as corrupt data. Data may be corrupted by duplicate entries, erroneous entries, software viruses, and unauthorized entries. Corrupt data may persist in the data processing system for some time before discovered. As a result, flash backups are not sufficient to protect valid data while removing corrupt data.
From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method that continuously protect data. Beneficially, such an apparatus, system, and method would make all data instances available for recovery to the data processing system.